Hot-air furnace



Oct. 16, 1928.

1,687,983 A. L. KLEEs ET AL HOT AIR FURNACE Filed June 9, 1927 5 sheets-sheet 1 Oct. 16, 1928.

A. L. KLEEs ET AL. HOT AIR FURNACE Oct. 16, 1928. 1,687,983

A.` L. KLEEs ET AL HOT AIR FURNACE Filed June'e, 1927 5 sheets-sheet 4 Oct. 16, 1928.

A. L. KLEES ET AL HOT AIR FURNACE Filed June 9, 1927 5 Sheets-Sheet S. S." K

,In vena/rf.'

Patented Oct. 16, 1928.

UNITED STA TES PATENT OFFICE.

AILBIEIRi'l L. KLEES, 0F YORK, BENJAMIN GREENFIELD, 0F JACKSON HEIGHTS, NEW YORK, AND GEORGE v13. ACKERMANN, OF CHICAGO, ILLINOIS, ASSIGNORS T0 -CRIBBEN & SEXTON COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 0F ILLL N OIS.

HOT-AIB FURNACE.

Application med June 9,

This invention relates particularly to hot air furnaces adapted to employ a fluid fuel, suoli' as gas, fuel oil, or the like.

The primary object of the invent1on 1s to provide a furnace of high efficiency whlch 1s adapted to heat and circulate air, which may be used for heating residences, or for other purposes.

A further object of the invention 1s to provide, in conjunction with the improved furnace, a humidifier adapted to supply moisture to the heated air, the humidifier being preferably designed to supply to the air moisture properly proportioned to correspond with the temperature to which the rooms are heated.

The invention is illustrated in a preferred embodiment in the accompanying drawings, in which- Fig. 1 is a broken plan view of a hot air furnace, partly in section, embodying the invention; Fig. 2, a broken vertical sectional view taken as indicated at line 2-2 of Fig. 1; Fig. 3, a vertical sectional view of one of the heating-burners employed, the section being taken as indicated at line 3 of Fig. 2; Fig. 4, a broken plan view taken as indicated at line 4; of Fig. 3; Fig. 5, a broken vertical sectional view taken as indicated at line 5 of Fig. 2 and showing one of the combustion-fines; Fig. 5a, a choker interchangeable with that shown in Fig. 5; Fig. 6, a perspective View of a pilot-burner; Fig. 7, ar reverse perspective view of the same; Fig. 8, a perspective view of the evaporator-pan and water-supply tank of the humidifier employed; Fig. 9, a broken sectional view taken as indicated at line 9 of Fig.v 8, and showing a detail o f a floatcontrol'valve employed; Fig. 10, a broken sectional view taken as indicated at line 10 of Fig. 1 and showing a detail of a fusedevice cont-rolling the electric circuits which control the blower-motor and fuel-valve, the fuse-device being preferably mounted in the upper portion of the hot-air flue of the furnace, as shown in Fig. 2; Fig. 11, a perspecti've view of the humidifier-burner; Fig. 12, an section taken as indicated at line 12 of `Fig. 11; Fig. 13, a broken plan view,- on

Fig. 11;

1927. vserial No. 197,697.

an enlar ed scale, of the burner shown in l ig. 14, a sectional view of a main automatically controlled fuel valve, the Sec tion being taken as indicated at line 14' of Fig. 2; Fig. 15, a sectional View of a bypass valve associated with said main valve, the section being taken as indicated at vline 15 of Fig. 2; Fig. 16, a plan sectional view taken as indicated at line 16 of Fig. 15; Fig. 17, a diagrammatic view illustrating the manner in which the automatic fuel-valve and blower-motor are controlled by means of a thermostat and safety-switch, said safety-switch. being controlled by a fuse or other suitable device; and Fi 18 is a broken sectional view of a modified orm of burnerorifice. i

Briefly, it may be statedhere that in the preferred construction the furnace is provided With a group of upright combustionflues, in front thereof with an adjacent group of return-dues, and in front of the return fines with a group of eXit-fiues which lead to the smoke-stack; also, that the furnace is equipped at its front side with a blower operated by an electric motor, said blower operating to force the air to be heated across and between the several groups of iues mentioned, the air to be heated coming first into contact with the relatively cool exit-fines, then into contact with the return-fines, and finally into contact with the highly heated combustion-dues, after which the air passes out through a hot-air flue, from which it is distributedby` means of suitable conduits, to the rooms to be heated; also, that the evaporator-pan of the humidifier is so dis- 1 posed in the base of the furnace as to supply 'moisture to the heated air as it passes lustrated, A designates a heating-chamber which may be of rectangular form and which is equipped at its front. side with an intake air-conduit A and which is equipped at its rear side with a hot-air flue A2; B, a blower provided with an intake conduit B and an outlet conduit B2 which communi- Cates with the conduit A; C, a group of combustion-filles which preferably are disposed in an upright position in the rear portion of the -air-heating chamber A; C', a group of return-ilues disposed in the chamber A immediately in front of the tlues C; C2, a group of outlet-flues, or eXit-lues, disposed in front of the return-dues; D, a chamber surmounting the heating-chamber above the combustion and return-dues; E, a chambersurmounting the heating-chamber above the eXit-lues and communi^ating with a smoke-stack E; F, a burner-chamber, within which are mounted heating-burners F one of which is shown in detail in Fig. 3; G, a sub-chamber disposed in front of the burner-chamber F and below the return and exit-fines, v'the chamber G being equipped with a drain-pan G from which leads a drain-pipe G2; H, a humidier comprising an evaporator-pan H, a water-supply tank H2, and a burner H3, the burner H3 being located in a burnerschamber H4 disposed back of the main burner-chamber F; I, a

.and superposed chambers.

pilot-burner (Figs. 2, 6 and T) which is adapted to light the main (heating) burners and the humidifier-burner; J, a fuel-supply pipe equipped with a thermostatically controlled main valve J and provided with a by-pass J2 equipped with a by-pass valve J3, the pipe J serving to supply the heating burners F and the humidifier-burner H3, as well as the pilot-burner I; K, an electric motor belted to a pulley on the shaft of the fan of the blower B; and L, an electric cir` cuit controlling the operation of the motor K and the main fuel-valve J said circuit being equipped with a thermostat L', a relay L2 and a fuse-controlled switch L3, as will be understood from Figs. 2, l() and 17.

The main portion of the body of the Jurnace consists of the heating-.chamber A, the surmounting chambers D and E, and the sub-chambers G and F. These chambers may be constructed in any desired manner. They may be formed conveniently, for the most part, from sheet-metal.

The furnace body is` provided with side walls l which may constitute the sides of the heating-chamber A and the sub-chambers The front, or leit hand side of the l'ieating-chamber, as viewed in Fig. Q, is open to the flaring conduit A which. communicates with the outlet-conduit B2 of the blower. The hot-air conduit A2 is parallel with the rear side of the heating-chamber A and is open thereto. The upper portion of the hot-air flue A2 communicates with a series of outlet-fines A3 which may lead to the rooms which are to be heated.

The rear wall of the hot-air flue A2 slopes at its lower portion, as indicated at 2; and back of this sloping wall is located a chamber A4 in which the tank H2 is conveniently located.

The lateral walls of the furnace preferably are provided with heat-insulating material. as appears from Fig. 1. Insulation may be used at other points, if desired. As shown at Fig. '2, insulation is used at the points 3, 4 and 5; and above the chamber D is a safety door, or closure D', adapted to relieve the pressure in case of an accumulation of gas and explosion thereof.

The heating-chamber A is provided with a top-plate 6 and a bottom-plate 7 which have perforations therethrough which receive the expanded ends of the tubes which constitute the combustion-fines, return-flues and exit-fines. v

The rear group of flues C, that is the combustion-lues, are shown as consisting of three transverse rows of upright tubes. These tubes preferably are equipped at their upper ends with chokers 8. Interchangeable chokers having passages of graduated sizes are provided, so that the correct size may be selected, according to the gas-consumption required. Their use renders unnecessary the regulation of the secondary air-supply and improves the result. In Fig. 5a, 8a designates one of the chokers which is interchangeable with the choker 8 shown in Fig. 5.

The heating-burners F', which may be termed the main burners, preferably are of the form shown in Fig. 3. Thus each burn- 'er comprises an elongated burner-head 9 which may be of approximately tubular cross-section, the burner-head being equipped at its upper side with a series of tubular, bosses 9a forming burner-orifices, and said chamber .9 having connected with its bottom wall at a central point a mixer tube 9b. The burner-head 9, the row of burner-orifices 9 thereon', and the mixer-tube 9b Vmay be of integral formation. They may, for example, be of cast-metal. The burner-orifices 9a are spaced apart in such a manner as to make a burner-orifice co-aXial with each combustionlue. The orifices 9El 'preferably are tted with perforate vdisks 9c of lava, encircled by a corrugated metal strip 9d which is interposed between the periphery of the lava disk and the encircling wall of the hollow boss. The manner 'f in which the burner-tip is located axially between a combustion-flue C is illustrated in Fig. 5. Those skilled in the art will understand that the space l0 between the burner-tip and the bottom of the combustion-flue should be properly adjusted.

The main burners F are mounted on horizontal bars 11 with which the burner-chamber F is equipped. The bars 11 may be vertically adjustable, if desired. A secondaryA air supply is admitted to the burner-chamber F through a register 12, which may be adjusted to admit the desired supply.

Aapassage 13 between the burner-chamber F and the burner-chamber H4 serves to permit the products of combustion from the humidifier-burner I-I8 to pass through the combustion-fines C. As shown in Fig. 2, the pilot-burner I is a tubular member located at the opening 13 and provided on opposite sides with perforations 14, whereby the iiames from the pilot-burner are directed towards the main burners and the humidifier-burner.y t

Thefuel-supply pipe J is equipped with nipples 15 through which gas may pass to the mixture-tubes 9 ofthe main. burners, as appears from Figs.l and 3. rlhe pipeJ has a branch 16 which supplies the pilot-burner I, the branch 16 being equipped with a pilotvalve 16a. The ipe J also has an extensionV 17 equippedwith) a valve 17 a through which the humidifier-burner Hs is supplied. The pipe J is provided with a hand-valve J* to enable the gas to be kept from the main burners and humidifier-burners until after the pilot has been lighted.

A gas-pressure regulator J 5 is provided in the course of the pipe J and is set to supply uniform pressure to the burners.

The drain-pan Gr is properly located in the sub-chamber G to collect condensation which may drain backfrom the iiues, chieiiy' the exit-hues C2, which are the coolest. It will be understood that the gases are hottest in the combustion-fines C; less hot in the return-fines C; and stillcooler in the exitiiues C2. The flues are properly pro ortioned to carry away the products of com ustion, taking intoconsideration the shrinkage in volume as the gases are cooled. The flues .of the several rowspreferably are staggered with relation 'to -each' other, as will be understood from Fig. 1. The purpose is to insure contact between the air which is being heated and the fines, as vthe air passes through the heating-chamber transversely with relation to the ues.

It is desirable to make the flues C2, particularly, of a metal which will be retsistant to corrosion from the gases and vapors passing therethrough, or the condensations collecting in the iiues and trickling back into the drainpanG..

The burner-chamber H* of the humidifier is surmounted by a plate, or hanger, 18. This plate is'lon'gitudinally slotted, and the body-portion 19 of the evaporator-pan H depends through the slot into the chamber H4. The pan is provided with a flange 19'l which rests upon the plate and is secured to the late b anchor bolts 20.

The tamil-Pis mounted on 4sup orts'21 llocated inthe base of the chamber 9. The

.burner going an through the medium of a lever 24 equipped with a ball float 24B. A pipe 25 connects the tank H2 with the evaporator-pan H. The evaporator-pan is equipped with an` overflow pipe 26. Water is maintained in the evaporator-pan at the -level-of the Water 51H2 the tank H2, as will be understood from The-humidifier-burner H3 is shown in detail in Figs. 11-13. Asshown, it comprises a pipe provided with a longitudinal slot 27 in which is held a corrugated strip 27. However, the burner may be Aof any suitable construction. l

The pilot-burner I'employed is shown in Figs. 6 and 7 g and from Fig. 2 it will be noted that the burner is so .disposed that it will serve to light the main burners and the evaporator-burner. e The arrangement of the 'by-pass 'J2 with relation to the automatic fuel-valve J '1s shown in Fig. 1. A detail of the main valve is shown in Fig. 14, from which it will be noted that the valve-stem is equipped'with a core 28 which co-acts with a solenoid 29, which, as shown in Fig. 17 forms a part of the electric circuit L. U

The by-pass vvalve J is shown in Figs. 15 and 16 as a Valvehaving a plug 30 whose stem is equipped with a handle 31. The plug is provided with a small passage 30 and at right angles thereto with a large passage 30". r The passage V30?*l the passage of suglcient gas to kee the. pilotalso, if desire to. malntain a low flame at the main burners and the humidifier-burner. If desired,l thevalve J3 may be open to permit passagebf gas through the large passage 30", 1n which case sufficient. gas will be permitted to ass to serve the burners to full capacity. T is 1s a desirable feature in case the electric circuit should fail'and the valve J thus fail to open. Obviously, lthe cock 30 may be set so. as to serve the burners at any desired capacity.

may serve to Y permit ius,A

The pilot-burner may be 'turned oii' whenl desired. I

Referring to Figs. 2 and 17, the main line wires of the electric circuit L are designated 32 and 33. The thermostat L is intended to be mounted in one of the rooms to be heated. It is connectedv with the relay L2 in a known manner, the wires 34 shown in the diagram extending through a conduit 34., as shown in Fig. 2. One of the wires 35, 3 5a leading to the motor and tothe solenoid 29 has interposed in its course wires 36 which lead through a conduit 36 L8, which, as shown in Fig. 2,"1's mounted in the upper portion of the hot-airj finel A2. The wires 36 are connected with switchpoints 37 and 38 shown dia ammatically in Fig. 17. As shown, in 1g. 10, these switch-points are mounted in a casing 39 and normally are heldin contact with each other by means of a lever 40 pivoted at 4l and having an arm 40a projecting through a slot 42 in the casing. The projecting end of the lever is connected by a fuse-link 43 with a stud 44 which projects from the switch-box., It will be noted that the fuselink 43 is exposed to the temperature of hot air in the flue A2; and should a dangerous rise in temperature occur, the fuse-link will release the lever 40 and permit the contact 37, which is a spring-contact, to separate from the contact 38. In `this manner, -one line leading to the motorA and solenoid` will be interrupted, thus stopping the operation of the blower and closing the valve J.

In Fig. 2, the wires leading to the motor and automatic fuel-valve are carried in a conduit 45.

The blower B may be equipped with any suitable fan. It is preferred, however, to employ a sirocco fan which is capable of passing' air at high velocity across the heating flues. This mode of operation greatly increases the effectiveness of the heat transfer.

'To lessen the noise which might be caused by the vibration of the fan, the intakeconduit B is connected to the fan-,casing through the `medium of a sleeve of soft flexible material, such as canvas, this sleeve being designated 46 in Fig. 1; also a canvas sleeve 47 is employed to connect the outlet nozzle B2 of the fan-easing with the intakeconduit A of the heating-chamber.

It will be understood that the intake-conduit B may be connected with a return-pipe from the rooms to be heated, if desired. The system may be operated with or without the use of the blower. Thus, in mild weather, it may operate without the use of the blower; and, in cold weather, the blower may be employed to increase the heating capacity of the plant.

It will be understood by those skilled in the art that in case of the use of oil for heating purposes, the flow of oil to the burners may be inducl by means of a blower in the usual manner; and, if desired, a separate supply for the humidifier-burner may be provided. In such case, if desired, the pipe serving the humidifier-burner may be a separatepipe, and may have its independent valve controlled by the same thermostat which controls the operation of t-he main burners. In the. improved furnace, an evaporatorpan adapted tov provide a large water area is preferably employed. The heat supply to the evaporator-burner may be regulated by the valve 1"?"1,` Theheat supplied by the humidifier-burner is'proportional to the heat supplied by themain burners, since the fuel supplied fto thlsiuinidiier-burner is proportional to the fuel supplied to the main burners. This is true regardless of Whether the burners operate at full capacity, or at partial capacity.

The lower the external temperature, the greater the heat which will be required to heat a building, and the greater the need for humidifying the heated air. It has been found that in a climate corresponding with the winter climate of the northern part of the United States, the comfort range of humidity in heated rooms ordinarily will be from 35% to 45% humidity in the air; and the percentage of humidity can be kept within the best range by supplying to the humidifying-burner about 10% of the fuel employed in the furnace. .Ordinarily this will be sufficient lto evaporate the necessary amount of Water to humidify the heated air to the proper degree. It will be understood, however, that the ratio between the fuel supplied to the main burners and the humidifier-- burner may be varied to meet the needs for varying climates and different seasons. the other hand, it is necessary to guard against too high an evaporation, which might lead to the condensation of vapor on the Windows; and, on the other hand', it is necessary toguard against too little evaporation, leading to discomfort on account of dryness of theheated a.ir. For rooms heated to about 70 F., about 38% to 40% humidity is desirable.

The operation of the improved furnace may be stated briefly:

The by-pass valve J3 is, in any case, left sufficiently open to supply the pilot-burner, and it may be left sufliciently open to maintain low llames in the main burners and humidifier-burner. When 4the temperature in the rooms d'rops below the desired teinperature, the thermostat L operates to close the electric circuit, thus opening the main fuel-valve J and setting the blower in operation. The operation continues until the teinperature in the rooms reaches the desired degree, when the thermostat serves to stop the operation of the motor and close the valve J. In the case of a dangerous rise in temperature, the fuse-link 43 will melt, thus permitting the switch L8 to open, thus interrupting the circuit. This Will stop the. operation of a,` blower and close the main fuel-valve J The lheat delivered, by the humidifier-burner is proportionate to the heat supplied by the main burners; hence, the amount of water evaporated will bear a certain relation to the heat employed in heating a building. The products of combustion from the humidifier-burner will pass through the combustion-fines C of the furnace and will ultimately reachl the smoke-stack. They Y ing) burner F2.

v-having passages 9 therethrou 'about the same. degree of heating. The gases passing through the eXit-iiues C2 will be so lowered in 'temperature that condensations` are likely to occur in the exit-iiues, and thus sulphurous acid may come in contact with the exit-hues. For this reason, it is preferred to make the exit-flues of non-corrosive metal which will withstand the attack of' the wet gases and sulphurous acid; The con.- densations will drain` back into the pan G', which should also be of non-corrosive metal. Ultimatel the condensed fluids will escape throu h t e pipe G2 to the sewer.

In ig. 18 is shown a modified main (heat- In this case the elongated burner-head is provided at its upper side with a series of orifices (one showin) having counter-sinks, or circular sockets, 1n which are mounted part-spherical burner-tipsl 9 h. These burner-tips may be -of lava or ot er refractory ffmaterial, if desired, vand the passages may be symmetrically arran ed throughout the area ofthe burner-tip. he burner-tip 1s shown secured in the socket by cement 9g. f Other embodiments of the invention will be described vin an application which` is in course of preparation, in which ap lication it is intended to -cla'im the princip e of the humidifier -in its broadest a plications as well as another species of the invention.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary'limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible, in view of the prior art.

What We regard as new, and desire to secure by Letters Patent, is:

1. Ina furnace, an air-heatin chamber, combustion-fines, return-fines, an exit-fines extending through said chamber, and means whereby air may circulate through said chamber `transversely across said lues, the incoming air coming first into contact with said exit-lines.

2. In a furnace, groups of combustion-fines, return-fines an exitflues extending across said chamber, and means for forcing air through said chamber transversely across said flues.

3. In a furnace, an air-heating chamber, a hot-air Hue at the rear of said chamber and open thereto, an intake air-duct connected with the open front side of said chamber, a grou of combustion-dues in the rear portion o said chamber, main burners associan air-heating chamber,

burner-chamber d their lower ends ated with saidl combustion-fines, a group of return-fines in front of said combustion-fines and communicating therewith, and a group of exit-flues in front of said return-flutes and communicating therewith.

4. Ina furnace, an .air-heating chamber open at its front and rear sides, a hot-air flue adjacent the rear side of said chamber and open thereto, an intake-conduit forming a front for said chamber, a group of upright combustion-'fines disposed in the rear por.-

tion of said chamber, a group of returnv flues disposed-in front of said combustionlues and communicating with the u per ends thereof, a vroup of exit-flues in fii'ont of saidreturn-figues and vcommunicating at their lower ends with said return-dues, a

beneath said combustionflues, and burners disposed in said burnerchamber.

5. *In a furnace, an air-heating chamber,

a sub-chamber affording their lower ends with said second subchamber, a chamber surmounting said groups of ues and affording communication between the same, a group of eXit-flues adjacent said return-fines and communicatin .at their lower ends with said. second vsu ,-chamber, an outlet chamber above s aid y exit-fines and communicating therewith,

burners in said burner-chamber, a hot-air ue affordinv a rear end for the air heatingchamber, and an inlet air-flue connected with the front end of the air-heating chamber. -6. In a furnace, an ,air-heating chamber, a hot-air iiue at the rear side thereof and communicating therewith, an air-inlet iiue at the front side of and communicating therewith, a blower connected with `said air-inlet iiue, a subchamber below the rear portion of said airheating chamber and aifording a burnerchamber, a second sub-chamber in front of said burner-chamber, a group of upright combustion-dues in the rear portion o f said air-heating chamber and communicatin at with said burner-cham er., a group lof return-iiues in front of said combustion-fiues and communicating at the1r lower ends with said second sub-chamber, eXit-iues infront of said return-fines and communicating at their lower ends with cation between the upper end of the coma burner-chamber beneath the rear portion of said first-named said heating-chamber bustion-flues and return-fines, and a smokestack communicating with the upper ends of said exit-lues.

7 In a furnace, a main burner for supplyl ing heat, a humidifier and a burner for supplying heat thereto, a common fuel supply-plpe having branches supplying said burners in predetermined ratio, and a thermostaticall controlled valve controlling the passage of fuel through said fuel supply- 1 e. p In a furnace, a main burner for heating purposes, a humidifier and a burner for supplying` heat thereto, an air blower, an electric motor for said blower, a valve controlling the supply of fuel to said burners, and a thermostat controlling said motor and valve.

9. In a furnace, an air-heating chamber, heating flues extending across the same, main burners associated with said heatingiiues, a hot-air iiue communicating with said air-heating chamber, a humidifier adapted to supply vapor to the heated air,

, a burner for heating said humidifier, a blower communicating with the air-heating chamber and a motor for said blower, a valve controlling the supply of fuel to the main burners and said second-mentioned burner, and a thermostat controlling the operation of said motor -andsaid valve.

10. In a furnace, an air-heating chamber, a hot-air flue affording an outlet therefrom, an air-inlet iue connected with said airheating chamber, combustion-fines, returnflues and exit-fines extending through saidair-heating chamber, a sub-chamber affording a burner-chamber disposed beneath said combustion-dues, .a sub-chamber forming means of communication between said return-lines and said eXit-flues, a humidifier having an evaporator-pan opening into the lower portion of s aid hot-air iue; a burnerchamber bene-ath said evaporator-pan, main lburners in said first-named burner-chamber,

a burner in said last-named burner-chamber,

ja pilot-burner disposed between the main burners and the second mentioned-burner, and a fuel supply-pipe communicating with said burners.

11. In a furnace, an air-heating chamber, a hot-air flue forming a back for said chamber, a group of upright combustion-filles in the rear portion of said air-heating chamber and arranged in a plurality of transverse rows, a sub-chamber affording a burner-chamber beneath said combustion- Hues, a plurality of elongated burners in saidv ity of transverse rows, a sub-chamber forming means of communication between the lower ends of the return-dues and eXit-iues, a chamber surmounting the rear portion of the air-heating chamber and afford-ing communication between the upper ends of the combustion-fines and return-dues, a chamber sui-mounting thc front portion of the airheating chamber and communicating with the upper ends of the exit-fines, means for draining the second-mentioned sub-chamber, and means for admitting air to the front portion of said air-heating chamber.

12. In a furnace, an air-heating chamber, a hot-air flue forming a back for said chamber, a group of upright combustion-fines in the rear portion of said air-heating chamber and arranged in a plurality of transverse rows, a sub-chamber affording a burnerchamber beneath said combustion-ues, a plurality of elongated burners in said burner-chamber, each burner being equipped with a series1 of burner-tips disposed beneath the :respective flues of the corresponding row, agroup of return-fines in front of said combilstin-flues and comprising a pluj rallty of transverse rows, a group of exitthe air-heating chamber and communicating v with the upper ends of the eXit-flus, ymeans for draining the second-mentioned subcham ber, a blower communicatinor with the vfront portion of said air-heatingchamber, a motor for actuating said blower, a pipe for supplying fuel to said burners, the passage of fuel through said pipe, and a thermostat controlling said motor and valve.

13. A furnace comprising an air-heating chamber, a hot-air flue forming a rear end for said chamber, means for circulating air through said chamber from the front side thereof, combustion-dues in the rear portion of said air-heatin chamber, return-fines in front of said com ustion-Iiues, exit-flues in front of said return-dues, a main burnerchamber disposed beneath said combustion- 'lues, main burners in said burner-chamber, a burner-chamber disposed back of said main burner-chamber and equipped with a burner, an evaporator-pan mounted vin the bottom'of said hot-air iiue over said secondmentioned-burner, a chamber back of said second-mentioned burner-chamber, a watertank in said last-mentioned chamber communlcating withsaid evaporator-pan, and ay float cont-rolled valve in said Vtank controlling the admission of Water thereto.

a valve controlling 1,687,983 l l l I '7 14. In combination with a furnace, heatfor conductin air to and away from said ing-burners, a fuel supply-pipe therefor, a aireheatng -o amber, main burners for valve controlling 'the passage of fuel through supplying heatlto said flues, a humidifier said pipe, a thermostat controlling the openand a burner for supplying heat thereto, and 15 5 ing of said Valve, a pilot-burner, a by-pass means for supplying' fuel to the main burners about said valve, and a Valve controlling and said second-mentioned burner at a presaid by-pasps, said last-named valve being determined ratio. adapted -to admit to full capacity fuel to the v main burners. ALBERT L. KLEES'.

' 10 15. In a furnace, an air-heating chamber, BENJAMIN GREENFIELD.

heating ues extending therethrough, means GEORGE B. ACKERMANN. 

